Struct actix_web::web::Data

pub struct Data<T>(_);

Application data.

Application data is an arbitrary data attached to the app. Application data is available to all routes and could be added during application configuration process with App::data() method.

Applicatin data could be accessed by using Data<T> extractor where T is data type.

Note: http server accepts an application factory rather than an application instance. Http server constructs an application instance for each thread, thus application data must be constructed multiple times. If you want to share data between different threads, a shared object should be used, e.g. Arc. Application data does not need to be Send or Sync.

If route data is not set for a handler, using Data<T> extractor would cause Internal Server Error response.

use std::cell::Cell;
use actix_web::{web, App};

struct MyData {
    counter: Cell<usize>,
}

/// Use `Data<T>` extractor to access data in handler.
fn index(data: web::Data<MyData>) {
    data.counter.set(data.counter.get() + 1);
}

fn main() {
    let app = App::new()
        // Store `MyData` in application storage.
        .data(MyData{ counter: Cell::new(0) })
        .service(
            web::resource("/index.html").route(
                web::get().to(index)));
}

Methods

impl<T> Data<T>

pub fn get_ref(&self) -> &T

Get referecnce to inner app data.

Trait Implementations

impl<T: 'static, P> FromRequest<P> for Data<T>

type Error = Error

The associated error which can be returned.

type Future = Result<Self, Error>

Future that resolves to a Self

fn from_request(req: &HttpRequest, _: &mut Payload<P>) -> Self::Future

Convert request to a Self

fn extract(req: &HttpRequest) -> Self::Future

Convert request to a Self

impl<T> Clone for Data<T>

fn clone(&self) -> Data<T>

Returns a copy of the value.

default fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> Deref for Data<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &T

Dereferences the value.